SMN is the last thing that needs a buff.

First off, Ruin and Ruin 2 do low damage because SMN is a DoT class, and all of the DoT damage added together combined with a more powerful base spell would skew SMN way beyond the other dps classes. Your pet's base spell makes up for the difference in damage from BLM and WHM base spells.

Second, the only thing wrong with Enkindle is the cooldown. It should be 1 min, but I assume the reason it is so long is so that you can't stack Rouse+Spur every time you use it.

Third, Tri-Disaster is low damage because it's bind utility, not meant to be AoE damage.

Finally, buffing any of the above complaints would make SMN even more overpowered than they currently are in PvP.